The prior art is replete with numerous different devices for dispensing a measured amount of a fluid or powdered material from a container.
For example, Allen in U.S. Pat. No. 2,693,301 teaches a dispenser for dispensing measured quantities of powdered materials such as sugar. The dispenser fits inside a container and includes an elongated tube which has a flared extension at its lower end. The flared extension forms the lower reservoir which is used to capture a pre-measured amount of powder from inside the container. Powder flows into the lower reservoir through a number of inlet tubes. The lower reservoir provides a measured volume for the contents of the container which are emptied when the container is inverted.
There are two apparent problems with the Allen device. First, Allen teaches positioning the lower reservoir tightly against the bottom of the container. It will be appreciated by those skilled in the art that fitting the lower reservoir tightly against the bottom requires closer tolerances and consequently, the manufacturing costs can increase. Secondly, since the inlet tubes are the only conduit for the material to enter the lower reservoir, clogging of these tubes can render the dispensing device inoperable.
Another example of the prior art is Yasso in U.S. Pat. No. 2,704,623. Yasso also teaches a dispensing device which fits inside a container. The dispensing device according to Yasso comprises a vertical tube which fits into the mouth of the container, and a measuring funnel which fits onto the lower end of the tube. The measuring funnel includes a number of inlet notches to allow the material to be dispensed to flow into the funnel. Similar to the teachings of Allen, the measuring funnel according to Yasso rests against the bottom of the container.
As was the case for Allen, the dispenser configuration of Yasso requires close tolerances in order to fit the lower reservoir against the bottom of the container. Furthermore, the lower reservoir, according to Yasso can be prone to clogging which can render the device inoperable. The configuration of the lower reservoir permits granular or large particles of a normally small grained material to fall and collect at the bottom edge of the lower reservoir. These larger particles can clog the notches thereby reducing or preventing accurate dispensing of a measured amount of material.
Ladwig in U.S. Pat. No. 3,224,652 also teaches a dispensing device which fits into a container. The premeasured dispensing device taught by Ladwig comprises a lower measuring chamber which is connected to the mouth of the container by a vertical dispensing tube. The lower measuring chamber rests on the bottom of the container and includes an inlet for the liquid or powder to enter into the lower measuring chamber. The device also includes a venting tube which determines how much fluid enters the measuring chamber. The venting tube comprises a tube which runs alongside the dispensing tube and is connected to the dispensing tube and the top of the measuring chamber through an inlet. The venting tube determines the amount of fluid which enters the lower chamber.
While Ladwig provides a pre-measured dispensing device, the structure of the Ladwig device is unnecessarily complicated. In the Ladwig device, the venting tube determines the amount of fluid which will enter the lower chamber. As will be appreciated by those skilled in the art, this design unnecessarily complicates the structure and thereby makes the device expensive to manufacture. Furthermore, the device as taught by Ladwig is not well suited for dispensing powdered materials because the venting tube which determines the amount of fluid entering the lower chamber would be easily plugged by particles of powdered material. Therefore, Ladwig teaches a device which is complicated to manufacture and limited to use with liquids or finely powdered materials.
While the known devices discussed above can provide an accurate measurement of a fluid or a powdered material to be dispensed, there are numerous problems associated with these prior devices. First, they are difficult and expensive to manufacture. Secondly, in these known devices the lower reservoir is positioned tightly against the bottom or side of the container. This tight positioning provides a closed volume which is used to capture the pre-determined amount of fluid or powder material. While these devices provide an accurate measuring volume, they can be susceptible to clogging of the lower reservoir which can ultimately render the device inoperable.